Adjustable gas block for an indirect gas operated firearm

Abstract

A firearm including a barrel, receiver, indirect gas system and an adjustable gas block designed to interface with the indirect gas system is provided. Four indexable positions of adjustment are provided for on the adjustable gas block. Positions of adjustment are selected based on the use of a silencer, use of under-powered ammunition, the presence of un-burnt powder and debris in the host firearms operating system, or if the weapon is being fired under “ideal” circumstances. The provided gas block is designed to function with an indirect gas operating system. Excess gas from the operating system is not vented from the gas block thereby generating excess flash and sound. No tool is required to manipulate the adjustment mechanism of the gas.

The invention claimed is: 
     
       1. A firearm with an adjustable gas block comprising:
 a receiver; 
 a barrel connected to the receiver, said barrel having a gas port; 
 a gas operating system; 
 a nozzle assembly having a front end, back end, middle portion, and internal void with means to communicate with the barrel and gas operating system through a plurality of ports which are spaced about the middle portion, said back end being received within and enveloped by a portion of the gas operating system and having an opening in operational communication with said gas operating system; 
 a gas block housing having a barrel receiving channel for a portion of the barrel to be contained therein, a gas nozzle receiving channel having a cylindrical bore which is above and runs parallel to a longitudinal axis of the barrel and the barrel receiving channel, the barrel receiving channel having a port in communication with the barrel, the gas nozzle receiving channel cylindrical bore containing a front portion of the nozzle assembly therein; and 
 said gas block housing further having a transverse groove formed therein to receive a rotatable knob, said transverse groove running transverse to said barrel axis between the front end of the gas nozzle receiving channel cylindrical bore and a generally planar, rearwardly facing portion of said gas block housing; 
 a rotatable knob fitted within said transverse groove and rotatable with respect thereto, said knob having a bore in substantially longitudinal alignment with the gas nozzle receiving channel cylindrical bore, said rotatable knob being coupled to said front portion of said nozzle assembly to retain and control rotational movement of the nozzle assembly. 
 
     
     
       2. The firearm with the adjustable gas block of  claim 1 , wherein said nozzle assembly has at least two ports about its middle portion, wherein each of the at least two ports can be selectively placed into communication with said barrel gas port. 
     
     
       3. The firearm with the adjustable gas block of  claim 1 , wherein said nozzle assembly has at least three ports about its middle portion which can be selectively placed into communication with said barrel gas port. 
     
     
       4. The firearm with the adjustable gas block of  claim 1 , wherein said nozzle assembly has four selectable positions of adjustment, three of said selectable positions placing a port into communication with said barrel gas port. 
     
     
       5. The firearm with the adjustable gas block of  claim 1 , wherein each port of said plurality of ports having a different size to regulate flow of gas into said gas operating system. 
     
     
       6. The firearm with the adjustable gas block of  claim 5 , wherein said rotatable knob has a plurality of selectable positions, all but one of said selectable positions correlating to position one of the plurality of ports of the nozzle assembly into communication with said barrel gas port, one of said selectable positions rotating said nozzle assembly into a position such that no gas port is in communication with the barrel gas port. 
     
     
       7. The firearm with the adjustable gas block of  claim 1 , wherein said rotatable knob has a front face, a rear face, and a generally annular body surrounding said central bore, said rotatable knob being received within said transverse groove with the knob rear face adjacent the front end of the gas nozzle receiving channel cylindrical bore and the knob front face adjacent the generally planar, rearwardly facing portion on said gas block housing. 
     
     
       8. The firearm with the adjustable gas block of  claim 1 , wherein the back end of the nozzle assembly protrudes from the rear side of said housing in alignment with the gas nozzle receiving channel. 
     
     
       9. The firearm with the adjustable gas block of  claim 8 , wherein the protruding rear end of said nozzle assembly is rearward of said barrel gas port. 
     
     
       10. The firearm with the adjustable gas block of  claim 9 , wherein said protruding rear end of said gas nozzle has an internal bore through which gas entering the nozzle through one of the plurality of ports travels to reach a rear end opening in said nozzle assembly, said rear end opening being in communication with said gas operating system. 
     
     
       11. The firearm with the adjustable gas block of  claim 1 , wherein said gas block has an opening that houses a spring and a detent, said spring and detent working in conjunction with a series of notches present on said adjustment knob to prevent unintentional rotation of said knob.